MySQL 5.7 reduced the maximum number of innodb_undo_tablespaces
from 126 to 95 when it reserved 32 persistent rollback segments
for the temporary undo logs. Since MDEV-12289 restored all 128
persistent rollback segments for persistent undo logs, the
reasonable maximum value of innodb_undo_tablespaces is 127
(not 126 or 95). This is because out of the 128 rollback segments,
the first one will always be created in the system tablespace
and the remaining ones can be created in dedicated undo tablespaces.
Also, implement MDEV-11027 a little differently from 5.5 and 10.0:
recv_apply_hashed_log_recs(): Change the return type back to void
(DB_SUCCESS was always returned).
Report progress also via systemd using sd_notifyf().
Because the default build configuration of the server will remain
at -DWITH_INNODB_AHI=ON, we want to test the instrumentation.
We make and revert the test adjustments in separate commits on purpose,
so that this commit can be easily reverted later if the default
build configuration is changed to -DWITH_INNODB_AHI=OFF.
The InnoDB adaptive hash index is sometimes degrading the performance of
InnoDB, and it is sometimes disabled to get more consistent performance.
We should have a compile-time option to disable the adaptive hash index.
Let us introduce two options:
OPTION(WITH_INNODB_AHI "Include innodb_adaptive_hash_index" ON)
OPTION(WITH_INNODB_ROOT_GUESS "Cache index root block descriptors" ON)
where WITH_INNODB_AHI always implies WITH_INNODB_ROOT_GUESS.
As part of this change, the misleadingly named function
trx_search_latch_release_if_reserved(trx) will be replaced with the macro
trx_assert_no_search_latch(trx) that will be empty unless
BTR_CUR_HASH_ADAPT is defined (cmake -DWITH_INNODB_AHI=ON).
We will also remove the unused column
INFORMATION_SCHEMA.INNODB_TRX.TRX_ADAPTIVE_HASH_TIMEOUT.
In MariaDB Server 10.1, it used to reflect the value of
trx_t::search_latch_timeout which could be adjusted during
row_search_for_mysql(). In 10.2, there is no such field.
Other than the removal of the unused column TRX_ADAPTIVE_HASH_TIMEOUT,
this is an almost non-functional change to the server when using the
default build options.
Some tests are adjusted so that they will work with both
-DWITH_INNODB_AHI=ON and -DWITH_INNODB_AHI=OFF. The test
innodb.innodb_monitor has been renamed to innodb.monitor
in order to track MySQL 5.7, and the duplicate tests
sys_vars.innodb_monitor_* are removed.
Oracle introduced a Memcached plugin interface to the InnoDB
storage engine in MySQL 5.6. That interface is essentially a
fork of Memcached development snapshot 1.6.0-beta1 of an old
development branch 'engine-pu'.
To my knowledge, there have not been any updates to the Memcached code
between MySQL 5.6 and 5.7; only bug fixes and extensions related to
the Oracle modifications.
The Memcached plugin is not part of the MariaDB Server. Therefore it
does not make sense to include the InnoDB interfaces for the Memcached
plugin, or to have any related configuration parameters:
innodb_api_bk_commit_interval
innodb_api_disable_rowlock
innodb_api_enable_binlog
innodb_api_enable_mdl
innodb_api_trx_level
Removing this code in one commit makes it possible to easily restore
it, in case it turns out to be needed later.
